Gear device



-March 29, 1938. w, s rrH, 2,112,253

GEAR DEVICE Filed May 25, 1936 Illlflllll INVENTOR ATTORNEYS WsZe y A miih Patented Mar. 29. 1938 UNITED STATES GEAR DEVICE Wesley L. Smith, Oranford, N. J.

Application May 25,

Claims.

This invention relates to an operating mechanism for the landing-gear of flying machines.

It is the object of my invention to provide an automatically operating mechanism for extending I 5 the landing-gear of flying machines and all types of aircraft of analogous nature preparatory to the landing of such machines and for retracting the landing-gear upon the initiation of flight.

It is the further object of my invention to provide a mechanism for the landing-gear of flying machines, the operation of which is automatically responsive to predetermined conditions in the state of flight of the machine. This mechanism may be rendered operative in response to the airspeed or buoyancy of the flying machine proportioned with respect to the tractive power which is available for the propulsion thereof.

It is the further object of my invention to provide an electric circuit containing a source of electric energy, an electric motor energized thereby and a plurality of switches interposed therein which may be conditioned preparatory to the landing of the flying machine or the initiation of flight thereby to effect the automatic operation a of the motor to actuate the landing-gear in its extending or retracting direction. My arrangement also provides switches which automatically interrupt the operation of the motor upon the conclusion of the extending or retracting movement of the landing-gear.

Other. objects and purposes of my invention will appearfrom the more detailed description of the invention following hereinafter taken in con-' junction with the accompanying drawing wherein:

Fig. 1 is a schematic diagram of the arrangement in accordance with my invention with certain parts shown in elevation and others in sec== tion, and

Fig. 2 is a longitudinal sectional view along the arc line 2-2 shown in Fig. 1;

In the drawing is shown a portion of an actuating mechanism for a landing-gear L designed to be attached to a flying machine of any type which is in retracted position while the machine is in flight and which is extended preparatory to the landing of themachine. Such landing-gear and mechanical actuating mechanism therefor is fully illustrated and described in the United States patent to Loening No. 1,563,384, December 1, 1925. Since the present invention is not concerned with the details of construction of such landing-gear it is merely illustrated schematically in the accompanying drawing.

In the illustrated embodiment of the invention 1936, Serial No. 81,732

the landing-gear is operated by a reversible electric motor M through the intermediary of suitable transmission means T.

The mode of energizing of the motor M constitutes the essence of the present invention and will now be described in detail. In the preferred embodiment of my invention an airtight casing A is suitably positioned upon any part of the flying machine. A sylphon I is mounted on the inside of casing A. The tube P leading to the interior of the sylphon may be connected to the pressure side of a Pitot-static airspeed indicator head. The inside of casing A is connected to the static tube S, and the difierentials in pressure thus arising upon the interior and exterior of the sylphon l cause it to extend and collapse between the limiting positions of the end plate 3| shown in full and dotted lines in Fig. 1. The movement of this end plate in turn causes the rocking of a switch 2 pivoted upon terminal 3 into selective contact with the terminals 5 and 4. This switch forms part of an electric circuit which includes a source of electric energy such as a direct current battery B, the electric motor M, limit switches U and D, and throttle switches 8I I described in detail hereinafter.

The control member for operating the propulsion of the flying machine, which may be represented by the throttle lever 6 pivoted at 1, controls a portion of the electric circuit to condition the operation of the electric motor in the proper direction for the actuation of the landing-gear. The throttle lever 6 shown in the full line position represents the power on position in which case the throttle is open and the machine is in normal flight. In the position shown in dotted lines on the right, the lever is in the power 0 position, in which case the throttle is closed and the machine is prepared for landing. As shown more clearly in Fig. 2, 4

the throttle lever 6 has projections 6a upon the rear face thereof which cooperate with conduc- ;..ve segments 8-H], and 9| I, which normally are displaced from respective cooperating electrical contacts Ba-Bb, Illa-40b, 9a-9b and Ha-I lb,.and which are adapted to be bridged by such segments. The arrangement of the several contacts resemble those shown in detail for contact segment 8 in Fig. 2 wherein the seg- 0 ment 8 is shown normally extending from the backing plate 31, having a layer of insulating material thereupon, bymeans of springs 38 surrounding pins 35 which guide the to and fro movement of the segment 8 into and out of conell tact with terminals 8a and 8b, suitably mounted in insulated relationship in the backing plate 31 from which extend the conductors 59 and respectively, forming part of the electric circuit shown in its composite form in Rig. 1.

The limit switches U and D forming part of the electric circuit and switches which are normally closed and which are opened to interrupt the circuit of the electric motor upon the travel of the motor in a predetermined direction for a predetermined extent in order to interrupt such circuit upon the complete extension or retraction of the landing-gear. A transmission mechanism for operating such switches in the manner described is fully described in the above patent to Loening. Switch D is operated so that it is open when the landing-gear is fully extended; at all other times it is closed. The switch U is opened when the landing-gear is fully retracted and is closed at all other times.

The operation of my novel circuit with conductors l2-2i extending between the several elements, as shown in the accompanying drawing, may be explained as follows:

When the flying machine is on the ground at rest the throttle member 6 is in its position to the right or in the power off position, thereby contact segments 9ii bridge their respective contacts 9a9b and llal lb. Also the sylphon i in the airtight casing is in its collapsed condition whereupon switch 2 is in its dotted line position and closes the circuit at contact d.- The switch D is in its open position as a consequence of the extension of the landing-gear at the time of the previous landing oi the machine. Thereupon if a circuit should be traced from the positive side of the battery to conductor H, switch H, motor M and conductor 20, it is found that the circuit is broken at the switch. D and the motor cannot be energized until the switching arrangement is modified. This is executed upon the start of a flight, whereupon the throttle lever 6 is thrown towards its position to the left or power on position. Thereby switches 9 and II are opened and switches 8 and ii) are closed. Although the circuit from the battery to the motor may now be traced through elements l7I0 l2-M2l, switches U 8 and 5, it is apparent that the motor cannot operate on account of the open circuit at 3 and 5 before a return to the negative side of the battery may be had. However when the flying machine attains a suflicient flying speed, thereby developing a predetermined pressure in the sylphon I, the switch 2, .in the position shown in Fig. 1 will complete the circuit for the motor to eflect a retraction of the landinggear. When the gear is fully retracted, switch U opens to break the circuit and to deenergize the motor. This condition prevails with the switch D closed and switch U open until the machine must be prepared for landing.

At the end 01' the flight the throttle lever 6 is thrown to the power ofl'" position which closes the switches II and I and opens switches 8 and I0. In tracing the circuit in the present condition it is found that although switch D is closed, the circuit is interrupted between the contacts 3 and 4 and the operation 01' the motor cannot take place. However as the air speed decreases and approaches the landing speed the sylphon i collapses and thereby bridges the contacts 3 and l by means of the switch 2. This movement completes the motor circuit from the plus side 0 the battery through conductor Il,

contact ll, conductor l3, motor M, conductor 20, switch D, conductor i8, switch 9, conductor II, switches 4 and 3, and conductor it to the negative side of the battery. The motor operates in a direction reverse from the previous operation to efiect the extension of the landing-gear. When the landing-gear is fully extended switch D opens and interrupts the motor circuit.

In the above description one specific arrangement has been described to attain a system which is responsive to the airspeed or the buoyancy of the airplane and to the percentage 01' the power therein for its propulsion in order to control the operation of the landing-gear. However any other arrangements may be availed to obtain the same results. Thus, the power eil'ect may be derived from the intake manifold pressure responsive device, centrifugal governor connected to the engine or the like. The airspeed raponse may be obtained from a Venturi tube, floating air paddle and analogous device. The landinggear may be operated by a mechanism employing fluid pressure such as gas or liquid. For multi-motored flying machines the power responsive means can be adjusted so that the device will respond to any percentage of the total power which is desired for any possible combination of engines. It is understood that various modifications will suggest themselves to those skilled in the art without departing from ,the spirit of the invention as set forth above, the scope of which is specified in the annexed claims.

What I claim is:

1. In a flying machine having a fluid pressure producing device responsive to the speed of the flying machine, a retractable landing gear and a reversible electric motor and its circuits for moving said landing gear between operative and inoperative positions; a speed responsive switch device for closing circuits in one direction and the other through said motor, said device including an electric switch, a sylphon, conduit means to connect the sylphon with the fluid pressure producing device, and an operative connection between said switch and said sylphon.

2. In a flying machine having a fluid pressure producing device responsive to the speed of the flying machine, a retractable landing gear and a reversible electric motor and its circuits for moving said landing gear between operative and inoperative positions; a' speed responsive switch device for closing circuits in one direction and the other through said motor, said device including a closed casing, a sylphon mounted in said casing, a conduit communicating with the interior 01' said sylphon, a second conduit communicating with the interior oi the casing externally of the sylphon, said conduits aflording communication with high and low pressure points of the speed responsive fluid pressure producing device, an electric switch mounted within said casing and adapted for circuit connection to the motor circuit, and an operative connection between said switch and said sylphon.

3. In a flying machine having a fluid pressure producing device responsive to the speed of the flying machine, a retractable landing gear and a reversible electric motor and its reversing circuits for moving said landing gear between operative and inoperative positions; a speed responsive switch device for closing circuits in one direction and the other through said motor. said device including a closed casing, a sylphon mounted in said casing, a conduit communicatmg with the interior of said sylphon, said conduits afi'ording communication with high andiow pressure points of the speed responsive iiuid pressure producing device, a conductive support mounted in said casing, a pair of fixed contacts spaced from said support on opposite sides there oi, said support being adapted for connection to a power source and the fixed contacts ioeing adapted for connection to the reversing circuits of the motor, a movable contact pivoted inter mediate its ends to said support and tiltahie to engage the respective fixed contacts, an arm pro jeotin'g irom the movable contact and fixedly attached thereto, and a iink connecting said sylphon and the free end 01' said arm.

90 after the starting of flight; mechanism to auto maticaily controi said operating device comprising means responsive to the airspeed of the machine, means the position of which corresponds to the power being developed Toy the power plant of said machine, and means governed by said first and second means to effect the operation of said mechanism.

5. "in a dying machine of the type having a retractable ianding gear and an operating device for extending said landing gear into its extended position preparatory to ianding and for withdrawing said gear into its retracted position after the starting of flight, mechanism to automaticaliy' controi said operating device comprising means responsive to the airspeed of the machine, means comprising the throttle control for the power piant of said machine, and means governed icy said first and second means to eflect the operation oi said mechanism.

- WESLEY L. SMITH. 

